The present invention relates generally to position determining apparatus. More particularly, the present invention relates to a system and an associated method for determining positional data associated with a selected target and for transmitting data to the selected target through the use of optical signals.
Many varied types of surveying devices and methods are available to facilitate the collection of data required for mapping and surveying operations.
For instance, U.S. Pat. No. 5,291,262 to Dunne, the inventor of the present application for letters patent, discloses a laser survey instrument operative to determine positional data associated with a selected target. The laser survey instrument generates an infrared laser pulse which is directed upon the target:. Transmission of the laser pulse to the selected target and reflection of the laser pulse back to the survey instrument permits determination of the range between the laser survey instrument and the selected target. The survey instrument also determines vertical and horizontal angles between the survey instrument and the selected target. The horizontal and vertical angles, together with the range between the survey instrument and the target, form positional data which defines the position of the selected target.
Also hand-held laser survey instruments available from Laser Technology, Inc. of 7070 South Tucson Way, Englewood, Colo. 80112, determine range, horizontal angle, and vertical angle values which together form the positional data which define the position of a selected target. The positional data determined by the laser survey instruments may be supplied to a data storage apparatus which records the data collected by the survey instrument.
A HYDRO II (tm) laser survey instrument and system is also available from Laser Technology, Inc. The survey laser determines the range between the survey laser and a selected target. A theodolite determines horizontal and vertical angles between the survey laser and the selected target. Values of the range and of the horizontal and vertical angles are supplied to continuous wave radio circuitry which modulates a continuous wave, radio frequency signal. A modulated radio frequency signal is generated by the radio transmitter for transmission to a remote site. The HYDRO II (tm) survey laser and system is of particular utility in underwater mapping operations. A ship-based sounding device, used to determine water depths, supplies data representative of measured water depths to ship-based data storage apparatus. A ship-based radio receiver receives the modulated signals generated by the radio transmitter of the HYDRO II (tm) survey laser system. The ship-based radio receiver demodulates the received signals, and values of the signals are stored at the ship-based data storage apparatus. By correlating the data determined by the survey laser and system with the data collected by the depth sounding apparatus, underwater mapping is permitted.
Similar survey laser and systems may be utilized in other applications to transmit data collected by the survey laser and system to a remote site.
The existing survey laser and system which transmits the data to a remote site through the generation of a continuous wave, radio frequency signal works well to transmit the data to a remote site. However, in many areas, governmental bodies regulate the transmission of radio frequency signals. In many areas, licensing is required to permit transmission of a radio transmitter. Multiple licenses are sometimes required to be obtained to permit operation of the radio transmitter when the survey laser and system is to be operated in various geographical areas over which various governmental bodies have jurisdiction. Procurement of the necessary licenses to permit operation of the radio transmitter can easily become a bureaucratic burden. Also, radio transmission of information by a continuous wave modulation technique is susceptible to radio frequency interference or frequency drift.
A laser survey instrument capable of collecting data and transmitting the data to a remote site by a transmission mechanism which does not require licensing by a governmental body would be advantageous.
It is with respect to these considerations and other background information relative to survey instruments that the significant improvements of the present invention have evolved.